1. Field of the Invention
The present invention relates generally to drug delivery devices, and more particularly to devices for storing, transporting and dissolving dry reagents.
2. Description of the Related Art
Medical treatments often involve solutions or suspensions of drugs or other reagents. Transporting and storing such solutions can be extremely expensive. Accordingly, it is advantageous to transport and store drugs or other reagents in a dry powdered or lyophilized form, reducing the bulk and weight, and to mix the reagents with a fluid just prior to administration.
U.S. Pat. No. 5,259,954 to Taylor, issued Nov. 9, 1993 (hereinafter “the '954 patent”) and U.S. Pat. No. 5,725,777, issued Mar. 10, 1998 (hereinafter “the '777 patent”) disclose a drug pack or “reagent module” suitable for storing dry reagents and for preparing solutions for administration by passing a fluid through the pack. Specifically, FIGS. 9-10 and 12-15 of the '777 patent illustrate two embodiments in which a porous compression element constantly exerts an inward force on the dry reagent bed, keeping the reagents compacted even as the bed is eroded by passing fluid through the porous compression element and through the bed. This arrangement advantageously enables efficient, uniform dissolution of the reagent bed.
While the reagent modules of the '954 and '777 patents operate well in storing and dissolving reagent beds efficiently, there remains room for improvement. Specifically, automated assembly of the disclosed compression elements is difficult, tending to result in mis-orientation and tangling. Furthermore, the foam compression elements disclosed in the '954 patent are difficult to disinfect and tend to retain any contaminants they are exposed to prior to assembly and during operation.
Accordingly, a need exists for improved drug delivery packs of the type disclosed in the '954 and '777 patents.